The use of fluoride in anticaries drug products, marketed in the U.S., is carried out under the guidance of the FDA's Fluoride Monograph, 21 CFR 355.10 (revised Apr. 1, 2012).
TABLE 1Concentration and Dosage of Stannous Fluoride in Dentifrice/Rinse/Gelproducts according to the Federal Register 21 CFR 355.10DentifricesDentifrices containing 850 to 1,150 ppm theoretical totalfluorine in a gel or paste dosage form.Stannous fluoride 0.351 to 0.474% with an availablefluoride ion concentration = 700 ppm for productscontaining abrasives other than calcium pyrophosphate.Stannous fluoride 0.351 to 0.474% with an availablefluoride ion concentration = 290 ppm for productscontaining the abrasive calcium pyrophosphate.PreventiveStannous fluoride 0.4% in an anhydrous glycerin gel, madetreatmentfrom anhydrous glycerin and the addition of suitablegelthickening agents to adjust viscosity.TreatmentStannous fluoride concentrate marketed in a stable form andrinsecontaining adequate directions for mixing with waterimmediately before using to result in a 0.1% aqueoussolution.Dentifrices
Fluoride Dentifrices have been shown in numerous clinical trials to be effective anticaries agents [Stookey, J. Dent. Res. 1990, 69 (Special Issue): 805-812] and have been recognized as a major cause of the remarkable decline in caries prevalence in many developed countries. Dentifrices have been widely adopted around the world as the principle means of delivering topical fluoride and obtaining caries preventive benefits.
“Washout” of various enamel protectant and enamel repair ingredients from enamel surfaces by saliva flow, eventually controls the effective residence time of various commercial fluoride, enamel protectant and enamel repair, brushing compositions. To improve enamel protectant and enamel repair effectiveness, commercial, professionally prescribed, fluoride, brushing compositions resort to high levels of fluoride, i.e. 5000 ppm for Rx toothpastes, gels and rinses and to approximately 22,000 ppm fluoride for “in-chair”, professionally applied varnishes. In addition, standard OTC fluoride toothpastes can contain up to 1500 ppm fluoride under the FDA's Fluoride Monograph.
The current market for fluoride brushing products includes: professional and consumer oral care, fluoride treatments, both OTC and Rx brushing products; including: toothpastes, gels, pastes and varnishes. As noted above, Rx fluoride toothpastes and Rx fluoride toothpastes are well outside fluoride Monograph levels containing up to 5000 ppm fluoride. Professional oral care, in-chair, fluoride varnishes contain up to about 22,000 ppm fluoride, while OTC fluoride toothpastes can contain up to 1500 ppm fluoride, the maximum level provided for the Monograph.
The American Dental Association (ADA); the Food & Drug Administration (FDA) and oral care professionals including: general practitioners, periodontists, orthodontists, pediatric dentists, etc. as a group; are generally concerned about the trend of increasing fluoride levels. These organizations and oral care professionals generally favor using lower levels of fluoride in various in-chair treatments and various OTC and Rx, oral care, home treatments for patients, provided that enamel protection and repair, achieved with lower fluoride levels, are comparable to the results reported for brushing products with higher levels of fluoride. This preference for lower fluoride-brushing products is driven by the concern over toxicity, fluorosis in children, etc., associated with exposure to high fluoride levels, long term.
It is generally accepted that approximately 90% of the fluoride used in OTC and Rx fluoride brushing treatments is expectorated after use. Thus, the window for fluoride treatment of enamel is essentially limited to the time fluoride is being brushed onto the enamel. In contrast, fluoride varnishes containing 22,000 ppm fluoride, applied to the enamel by an oral care professional, are designed to maintain substantive fluoride levels on the enamel after patient expectoration.
Fluoride varnishes are generally applied professionally, at a frequency of about once every six months with the target audience comprising primarily children.
Dietary fluoride levels have gradually increased due to fluoridated drinking water and the fluoride in water used in food preparation, etc. In addition, most consumers use fluoride: toothpastes, rinses, gels, etc. Extensive literature citations indicate topical fluoride treatments are more effective in protecting and repairing enamel than treatment with systemic fluorides.    See: Ripa, Public Health Dent., 1991; 51:23-41.
Yet, with all this fluoride available, caries continues to pose a challenge: in children, as well as adults including coronal caries in the elderly, caries in dry mouth patients, caries in immunocompromised patients, caries in patients undergoing medical or dental treatment, etc.
There is a need to improve enamel protectant and enamel repair effectiveness treatments for professional oral care, fluoride procedures, as well as for OTC fluoride products for patient treatment, while reducing the risk associated with exposure to high fluoride levels.
Additionally, there is a need to improve the efficacy of fluoride products in the area of enamel protection and enamel repair, where the efficacy of various fluoride treatments is assessed as a function of the fluoride level used to effect treatment of various conditions of the enamel.